Vapor barrier means for underground storage system

ABSTRACT

1,180,416. Liquefied gas storage chambers. INSTITUTE OF GAS TECHNOLOGY. 14 Feb., 1967 [14 Feb., 1966 (3)], No. 7040/67. Heading F4P. The floor, sides and roof of an excavated underground rock cavern 8, Fig. 3, at the bottom end of an inclined adit 3 for storing liquid methane at atmospheric pressure are first sealed at 101, 121, Fig. 4, against inflow of water, the roof and sides are then lined with foam-in-place insulation material 103, e.g. polyurethane which in turn is lined by layers 105, 106 of rigid polyurethane foam panels whilst the floor is lined by layers 107a, 106a formed of rigid polyurethane panels, and the roof sides and floor are then sealed by an impermeable barrier layer 111, e.g. of aluminum and finally the adit is closed at a point above the stored liquid level by a vapour barrier means 6 through which pass service lines. Abutting edges of the panels of layers 105, 107a are sealed by non-setting mastic whereon abutting edges of the panels of layers 106, 106a are sealed by flexible foam 113, Fig. 5, and by flexible tape. The barrier 6 comprises a doublewalled steel frame 211, Fig. 10, bolted to a concrete frame 207 set in the walls, floor and roof of the adit, and an access opening 219 in frame 211 is closed by a removable cover 223. In operation air is displaced from the cavern by inert gas delivered from a source 25 through initial cool-down spray lines 26 and the liquid fill line 30, whilst return purge gas is exhausted through a liquid withdrawal line 38 and a vapour return line 32. Initial liquid injection is through lines 26 and nozzles 28 and displaced gas returning through line 32 is flared at 48 until said return gas comprises pure methane after which the return gas is either re-liquefied at 50 or delivered to a consumer line 49. When cooldown is completed liquid methane is fed to the cavern through fill line 30 and may be withdrawn by a pump 56 discharging through a line 38 into a vaporizer 35.

Aug. 13, 1968 A, R. KHAN ETAL 3,396,539

VAPOR BARRIER MEANS FOR UNDERGROUND STORAGE SYSTEM Filed Feb. 14, 1966INVENTOR. PHILLIP J. ANDERSON AMANULLAH R. KHAN 9 BERT E. E'AK/N ,4TTORNEYS' United States Patent 0 3,396,539 VAPOR BARRIER MEANS FURUNDERGRGUND STORAGE SYSTEM Amanullah R. Khan, Chicago, Bertram E.Eairin, Naperville, and Phillip J. Anderson, Deeriieid, Ill., assignorsto Institute of Gas Technology, a not-for-profit corporation of IllinoisFiled Feb. 14, 1966, Ser. No. 527,288 6 Ciaims. (Cl. 61-.5)

ABSTRACT OF THE DISCLOSURE A vapor and liquid barrier structure mountedin an inclined adit between the atmosphere and an underground chamberused for storing liquefied gas at atmospheric pressure and cryogenictemperatures. A rigid outer frame is rigidly secured to the wall,ceiling, and floor of said adit. The outer frame includes a centralaperture in which a second rigid frame is received. The second rigidframe, in turn, includes a central aperture therein which is enclosed bya removable plugging member. The joints be tween the inner and outerframes and between the inner frame and the plugging member are sealed bymeans for preventing passage of liquid and vapor therethrough.Insulation is contiguous with the outer frame, the inner frame, and theplugging member to substantially reduce the transfer heat from theatmospheric side of the barrier to the cryogenic liquefied gas containedwithin said underground chamber.

This invention relates to means for sealing the entry adit to anunderground storage cavern for storing liquefied gases. In particular,the invention relates to an insulated composite concrete-metal barrierwall for placing in an adit leading to an underground rock storagecavern.

There is described in our copending application Ser. No. 527,158, filedFeb. 14, 1966, a new and improved method for storing large volumes ofliquefied gases underground at substantially atmospheric pressure in asafe and economical manner. The invention described in theaforementioned application relates generally to the storage of liquefiedgases in rock caverns or rock structures near the ground surface, thecaverns or structures being insulated and lined to provide lowevaporation rates and safe containment of the low temperature liquidgases at substantially atmospheric pressure. The caverns were designedto store liquefied natural gas but may also be used for storage of othergases which have been cooled to the liquid state at atmosphericpressures such as ethane, propane, butane as well as ammonia, carbondioxide, argon, nitrogen and hydrogen.

The underground rock storage caverns with which the vapor barrier ofthis invention is particularly useful comprise a room and pillar cavernwhich has been excavated by means of a large inclined entry whichpermits rapid ingress and egress of heavy equipment for the purpose ofefficient and economical excavation. The walls, roof and pillars of thecavern are coated with a moisture or water sealant and all rock surfacesare insulated with one or more layers of a foamed insulating materialproviding internal insulation in the cavern. One layer of theinsulation, preferably the innermost layer, is coated or lined with aliquid and vapor impervious material, such as a laminate of plastic andmetal foil, to prevent loss of liquid or vapor through the insulation.

The entry adit of the cavern is provided with a double bulkhead systemwhich prohibits gas or liquid from leaking from the cavern through theadit to the ground level. The bulkhead system comprises a liquidbulkhead which serves as a weir as described in copending applicationSer. No. 527,158, filed Feb. 14, 1966, and a vapor barice rier throughwhich are provided suitable apertures for piping means for filling,emptying, relieving and instrumenting the rock cavern. Such vaporbarrier means is the subject matter of this invention.

It is an object of this invention to provide a vapor barrier means inthe large inclined entry adit to an underground storage cavern whichmeans prevents leakage of vaporized gases from the cavern to atmosphereand also prevents heat loss to the cavern.

It is a further object of this invention to provide such vapor barriermeans which is relatively simple of construction and which provides easyaccess to the cavern in the event the cavern is to be opened.

It is yet another object of this invention to provide a vapor barriermeans through which may be inserted various piping means for filling,emptying, relieving and instrumenting the rock cavern in the storage ofliquid gases.

Other objects of the invention will become clear as the invention ismore fully described hereinafter.

In one of the important aspects of the present invention, a vapor andliquid barrier structure, mounted in an inclined adit between theatmosphere and an underground chamber used for storing liquefied gasesat substantially atmospheric pressure and cryogenic temperaturesincludes an outer rigid frame having an enlarged central opening,suitable means for rigidly securing the outer rigid frame to the wall,floor, and top of a portion of said adit, an inner rigid frame having acentral aperture, suitable means for securing the inner rigid framewithin the enlarged central opening of the first rigid frame, a pluggingmember removably secured within the central aperture of the inner rigidframe, sealing means on the joints between the inner and outer framesand between the inner frame of the plugging member for preventing thepassage of liquid and vapor therethrough, and insulation substantiallycontiguous with the outer frame, the inner frame, and the pluggingmember for substantially reducing the transfer heat from the atmosphericside of the barrier to the cryogenic liquefied gas side of the barrier.

In the drawings:

FIG. 1 is a front elevation showing the vapor sealing meglns as itappears in the inclined entry of a rock cavern; an

FIG. 2 is a top view along line 22 of FIG. 1.

Broadly speaking, the vapor barrier of this invention consists of a castconcrete frame which is keyed into the walls, floor, and roof of theinclined entry and is held to the rock surface by a plurality of anchorbolts which are embedded in the rock and extend into the concrete frameto restrict relative movement between the frame and the rock. Mountedwithin the concrete frame is a doublewalled metal frame which has aplurality of apertures to accommodate piping, conduits and the like andan access hole at its center sufficiently large for ingress and egressof workmen. The access hole is closed during normal operation of thecavern by a double-walled plug described hereinafter. The double-walledmetal frame and plug are insulated internally to minimize heat lossbetween the cavern and atmosphere. The metal frame is fabricated withexpansion means to allow differential movement between the concreteframe member and the metal frame member in response to thermal stresses.The metal frame is made of any material which will not exhibit brittlefailure at cryogenic temperatures, preferably a suitable grade of steel.All piping and lines which pass from atmosphere into the cavern passthrough the doublewalled metal frame through the above-mentionedapertures where a gas-type seal and suitable expansion and contractionmeans are provided on the surface of the metal frame toward the storagecavity to accommodate thermal stresses.

Referring to FIG. 1, there is shown generally at 1 in cross-section anarched dome entry adit having a rock surface. As best seen in FIG. 2,the walls of the adit are keyed at 3 by providing a circumferentialgroove along a substantially vertical plane. Rock bolts 5, well-known inthe mining art, are driven into the walls at the base of keyed portion 3at various points as best seen in FIG. 1. The rock bolts projectperpendicularly from the rock wall and are embedded in concrete frame 7which fills the keyed at 3 by providing a circumferential groove along aframe with a large, generally square opening 9.

Disposed within the opening 9 is a double-walled metal frame 11 providedwith expansion means 13 which are simply creases projecting from themetal frame. Such expansion means permit lateral and vertical expansionand contraction of the metal wall in response to thermal stresses. Metalwall 11 is oriented in the entry adit so that the side thereof withexpansion means 13 (lower side in FIG. 2) faces inwardly toward thecavern and the other side of the frame 11 faces outwardly towardatmosphere. Thus the inward side of the frame 11 is subjected to thegreatest thermal stresses. Metal wall or frame 11 is secured to theconcrete frame 7 by means of plates 15 which overlap opposite sides ofthe concrete frame 7 and wall the frame 11 and which are welded onto themetal frame 11 and bolted through the concrete frame as shown at 17.

The central portion of the metal wall or frame 11 is provided with anaccess hole 19 which is normally bolted closed by cooperating boltingmembers 30 and 31 to the metal frame 11 by means of a double-walled plug21 as shown at 23. Both the metal frame 11 and the plug 21 areinternally insulated with a suitable cryogenic insulating material 14,such as glass fibers or polyurethane foam. Through the metal wall 11 areprovided apertures 22 which are adapted to accommodate piping andconduits extending from outside the cavern to within the cavern.Suitable gas sealing means and expansion joints are provided to ensuregas-tight integrity of the barrier.

The edges of the contact of concrete frame 7 and the metal wall 11 aresealed by means of vapor impervious cryogenic adhesive tape 27 which issecured to the insulation 29 provided on the internal surface of theconcrete frame and on the internal surface of the rock cavern asdescribed in copending application Ser. No. 526,983, filed Feb. 14,1966, and to the wall of the metal wall frame 11 which faces the cavern.In addition, the contact edges between the plug 21 and the metal wall 11are sealed by means of suitable adhesive tape 29a, such as tape 23, onthe wall of 11 facing atmosphere. Such external sealing is necessarysince it is not possible to seal the joints of plug 21 and frame 11internally inasmuch as plug 21 is inserted into aperture 19 from theentry portal side or outer side of the vapor barrier.

As shown in FIGS. 1 and 2, the vapor barrier of this invention providesa simple, economical and effective means against loss of liquid or vapormaterials from within the rock cavern to atmosphere. Also the barrierinsulates the cavern from atmosphere. The barrier is sealed at alljoints by vapor-impervious cryogenic tape and the barrier is providedwith suitable expansion means so there is no possibility of rupture ofjoints during the thermal stresses encountered in filling or emptyingthe cavern. The internal portion of metal wall frame 11 is subjected tothe greatest thermal stress and is therefore made of special materialswhich do not exhibit brittle failure at cryogenic temperatures. Theouter portion of the metal frame 11 can be made of ordinary carbon steelsince such portion is not subjected to high temperature changes.

It should be clear to those skilled in the art that variousmodifications can be made in the above described invention within thespirit of the invention which we intend to be limited solely by theappended claims.

We claim:

1. A vapor and liquid barrier structure mounted in an inclined adit andbetween the atmosphere and an underground chamber used for storingliquefied gases at substantially atmospheric pressure and cryogenictemperatures, said adit having surrounding walls, a floor, and a top,said structure comprising an outer rigid frame having an enlargedcentral opening, means for rigidly securing said outer frame to saidwalls, floor, and top of said adit, an inner rigid frame having acentral aperture therein, means for rigidly securing said inner rigidframe within said enlarged central opening of said outer rigid frame, aplugging member, means for removably securing said plugging memberwithin said central aperture, means for sealing the joints formedbetween said outer frame and said inner frame and between said innerframe and said plugging member to substantially prevent the passage ofliquid and vapor therethrough, and insulating means substantiallycontiguous with said outer frame, said inner frame, and said pluggingmember to substantially reduce the transfer of heat from the atmosphereside of said barrier to the cryogenic liquefied gas side of saidbarrier.

2. The structure of claim 1 wherein said outer frame is formed ofconcrete, and said first mentioned securing means comprises a pluralityof rock bolts which are embedded in both said walls, said floor, andsaid top, and in said concrete, and a keyed groove provided in saidwalls, said floor, and said top for receiving said concrete outer frame.

3. The structure of claim 1 wherein said inner frame includes means forreceiving a plurality of pipes and conduits for passage thereof throughsaid structure.

4. The structure of claim 1 wherein said insulating means comprisesinsulation covering the cryogenic temperature side of said outer frame,and insulation contained within said inner frame and said pluggingmember.

5. The structure of claim 1 wherein said inner frame and said pluggingmember each comprise a double-walled metal panel, and said inner frameincludes means on the cryogenic side of said structure for permittinglateral and vertical expansion and contraction of said inner frame inresponse to thermal stresses.

6. The structure of claim 5 wherein each of said double-walled panelsincludes a space therein and said insulating means is received withinsaid space of each said panels.

References Cited UNITED STATES PATENTS 2,787,125 4/1957 Benz 61-.52,855,757 10/1958 Meade 6l--.5 2,981,070 4/1961 Seely 61-.5 3,151,41610/1964 Eakin et a1. 61.5 X 3,184,922 5/1965 Anton 61-.5

FOREIGN PATENTS 963,038 7/1964 Great Britain.

EARL J. WITMER, Primary Examiner.

